// 处理响应头中间件
module.exports=async (ctx,next)=>{
    const contentType='application/json;charset=UTF-8'
    ctx.set('Content-Type',contentType)
    ctx.set('Access-Control-Allow-Origin','*')
    ctx.set('Access-Control-Allow-Methods','OPTIONS,GET,PUT,POST,DELETE')
    await next()
}
